The low instrumental background of Suzaku, and the superior low-energy response of the XIS CCDs particularly in the first few years after launch, shed additional light on this topic: the radial profiles of Mg/Fe, Si/Fe, and S/Fe were consistently shown to remain uniform (i.e. all four elements showed a radially decreasing profile) in HCG 62 [1]}, NGC 5044 [2]}, NGC 507 [3]}, and NGC 1550 [4]} over the entire area probed by the Suzaku observations. A sample of 4 groups consisting of MKW4, HCG62, NGC1550, and NGC5044, was covered by Suzaku out to as far as 0.5 \(r_{180}\) , confirming that the Mg/Fe and Si/Fe ratios remain nearly constant and close to the Solar ratio [5]} out to a significant fraction of the virial radius [6]}. All these measurements are consistent with an \(N_{cc}/N_{Ia}\)  of 3–4 [7]}, [2]}, [4]}. For the supernova yields assumed in these works, \(N_{cc}/N_{Ia}=3\)  corresponds to a \(f_{\rm Fe,Ia}\)  of 80%, in line with the XMM-Newton results discussed in the previous paragraph.
A point of contention in the Suzaku results remained the O abundance, that seemed to have much shallower radial gradients than all other \(\alpha \) -elements (a conclusion shared by all references mentioned earlier in this paragraph). This would imply increasing O/Mg and O/Si ratios as a function of radius; since all these three elements are predominantly produced by SNcc, it is impossible to reconcile these measurements with a simple model where the relative contribution from SNIa and SNcc varies with distance from the BGG. It is likely that residuals in modeling the Galactic absorption and/or OVIII foreground emission, or issues related to Solar Wind Charge Exchange (whose strongest emission also comes from O), may have affected the measurements.
